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Title: Spin-polarized photoelectrons from half-filled-shell atoms

Abstract

A spin-polarized beam of photoelectrons of significant intensity from a closed ns{sup 2}-subshell of a spin-aligned atom having a multielectron half-filled subshell in its ground state is predicted. The polarization results from the specific properties of a half-filled shell atom due to the unbalanced exchange interaction between spin-up and spin-down electrons in the atom, both at the independent-particle and multielectron correlation levels. This mechanism causing the preferable spin orientation of outgoing photoelectrons differs from the commonly known mechanisms yielding spin-polarized photoelectrons from atoms. Calculated results for the photoionization of the valence 4s{sup 2} subshell of a spin-up oriented Mn(4s{sup 2} {sup 6}S) atom employing spin-polarized Hartree-Fock and random-phase approximation with exchange are presented, but the results are inherent properties of any half-filled subshell atom. The importance of electron correlation effects is emphasized.

Authors:
 [1];  [2]
  1. Department of Physics and Earth Science, University of North Alabama, Florence, Alabama 35632 (United States)
  2. Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States)
Publication Date:
OSTI Identifier:
20982115
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.022701; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; BEAMS; ELECTRON CORRELATION; ELECTRONIC STRUCTURE; ELECTRONS; EXCHANGE INTERACTIONS; GROUND STATES; HARTREE-FOCK METHOD; INNER-SHELL IONIZATION; MANGANESE; PARTICLES; PHOTOIONIZATION; PHOTON-ATOM COLLISIONS; POLARIZATION; RANDOM PHASE APPROXIMATION; SPIN; SPIN ORIENTATION; VALENCE

Citation Formats

Dolmatov, V. K., and Manson, S. T.. Spin-polarized photoelectrons from half-filled-shell atoms. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.022701.
Dolmatov, V. K., & Manson, S. T.. Spin-polarized photoelectrons from half-filled-shell atoms. United States. doi:10.1103/PHYSREVA.75.022701.
Dolmatov, V. K., and Manson, S. T.. Thu . "Spin-polarized photoelectrons from half-filled-shell atoms". United States. doi:10.1103/PHYSREVA.75.022701.
@article{osti_20982115,
title = {Spin-polarized photoelectrons from half-filled-shell atoms},
author = {Dolmatov, V. K. and Manson, S. T.},
abstractNote = {A spin-polarized beam of photoelectrons of significant intensity from a closed ns{sup 2}-subshell of a spin-aligned atom having a multielectron half-filled subshell in its ground state is predicted. The polarization results from the specific properties of a half-filled shell atom due to the unbalanced exchange interaction between spin-up and spin-down electrons in the atom, both at the independent-particle and multielectron correlation levels. This mechanism causing the preferable spin orientation of outgoing photoelectrons differs from the commonly known mechanisms yielding spin-polarized photoelectrons from atoms. Calculated results for the photoionization of the valence 4s{sup 2} subshell of a spin-up oriented Mn(4s{sup 2} {sup 6}S) atom employing spin-polarized Hartree-Fock and random-phase approximation with exchange are presented, but the results are inherent properties of any half-filled subshell atom. The importance of electron correlation effects is emphasized.},
doi = {10.1103/PHYSREVA.75.022701},
journal = {Physical Review. A},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • It is predicted that the near-threshold nondipole photoelectron angular distribution parameters of valence ns electrons from atoms having an nd{sup 5} half-filled shell in the ground state differ markedly for different final-state terms of the residual ion. This is due to the strong term dependence of electron correlation in these systems. As an example, the nondipole 4s-photoelectron angular distribution parameters below the 3d ionization threshold of the Mn(3d{sup 5}4s{sup 2} {sup 6}S) atom, leading to Mn{sup +}(4s{sup 1} {sup 7}S) and Mn{sup +}(4s{sup 1} {sup 5}S), have been calculated within the framework of the 'spin-polarized' random phase approximation with exchange.more » The phenomenon should be a general property of all half-filled shell atoms and ions.« less
  • We report a spin analysis of core-level photoelectrons excited by circularly polarized x rays from a nonmagnetic solid. In a combined experimental and theoretical study, we show that the spin-orbit-split W 4{ital f}{sub 7/2} and 4{ital f}{sub 5/2} photoemission lines from W(110) exhibit high spin polarizations of opposite sign that vary with energy and emission direction. These results suggest the study of the magnetic structure of nonmagnetic/ferromagnetic interfaces formed on high-atomic-number substrates by spin-polarized photoelectron diffraction. {copyright} {ital 1996 The American Physical Society.}
  • A theoretical prediction of a new spin effect by Tamura, Piepke, and Feder has been experimentally verified: Photoelectrons can be polarized even if the photoemission is performed with linearly polarized radiation and even if it is studied in the highly symmetrical setup of normal incidence and normal emission. Radiation with energies between 21 and 22.4 eV ejects photoelectrons from Pt(111) polarized with a degree between 10% and 40%. The spin direction coincides with a plane parallel to the surface and changes its sign when the crystal is rotated by 60/sup 0/ about the surface normal.
  • We report the first measurements of elastic scattering of spin-polarized electrons from spin-polarized Na atoms as a function of scattering angle. The incident energy is 54.4 eV, and the angular range is 20/sup 0/--135/sup 0/. Data are presented as an exchange asymmetry and a spin-orbit asymmetry. Each asymmetry has a magnitude of 3% to 4%, indicating that both the exchange and spin-orbit interactions must be taken into account to predict our experimental results.